Commit b65769fc authored by Finn Thain's avatar Finn Thain Committed by Geert Uytterhoeven
Browse files

m68k: Fix off-by-one calendar month 



This fixes a bug in read_persistent_clock() which causes the system
clock to lag the Real Time Clock by one month. The problem was noticed
on a Mac, but theoretically it must also affect Atari, BVME6000 and Q40.

The tm_mon value in the struct rtc_time passed to mach_hwclk() is
zero-based, and atari_mste_hwclk(), atari_tt_hwclk(), bvme6000_hwclk(),
mac_hwclk() and q40_hwclk() all make this adjustment. Unfortunately,
dn_dummy_hwclk(), mvme147_hwclk(), mvme16x_hwclk(), sun3_hwclk() and
sun3x_hwclk() fail to decrement tm_mon.  Also m68328_hwclk() assumes
a one-based tm_mon.

Bring these platforms into line and fix read_persistent_clock() so it
works correctly on all m68k platforms.

The datasheets for the RTC devices found on the affected platforms
all confirm that the year is stored as a value in the range 0-99 and
the month is stored as a value in the range 1-12. Please refer to the
datasheets for MC146818 (Apollo), DS1643 (MVME), ICM7170 (Sun 3)
and M48T02 (Sun 3x).

Reported-by: default avatarStan Johnson <userm57@yahoo.com>
Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 4eee57d6

arch/m68k/68000/timers.c

+3 −1
Original line number Diff line number Diff line
@@ -125,7 +125,9 @@ int m68328_hwclk(int set, struct rtc_time *t) 
{

	if (!set) {

		long now = RTCTIME;

		t->tm_year = t->tm_mon = t->tm_mday = 1;

		t->tm_year = 1;

		t->tm_mon = 0;

		t->tm_mday = 1;

		t->tm_hour = (now >> 24) % 24;

		t->tm_min = (now >> 16) % 60;

		t->tm_sec = now % 60;

arch/m68k/apollo/config.c

+5 −3
Original line number Diff line number Diff line
@@ -221,8 +221,10 @@ int dn_dummy_hwclk(int op, struct rtc_time *t) { 
    t->tm_hour=rtc->hours;

    t->tm_mday=rtc->day_of_month;

    t->tm_wday=rtc->day_of_week;

    t->tm_mon=rtc->month;

    t->tm_mon = rtc->month - 1;

    t->tm_year=rtc->year;

    if (t->tm_year < 70)

	t->tm_year += 100;

  } else {

    rtc->second=t->tm_sec;

    rtc->minute=t->tm_min;
@@ -230,8 +232,8 @@ int dn_dummy_hwclk(int op, struct rtc_time *t) { 
    rtc->day_of_month=t->tm_mday;

    if(t->tm_wday!=-1)

      rtc->day_of_week=t->tm_wday;

    rtc->month=t->tm_mon;

    rtc->year=t->tm_year;

    rtc->month = t->tm_mon + 1;

    rtc->year = t->tm_year % 100;

  }



  return 0;

arch/m68k/kernel/time.c

+7 −7
Original line number Diff line number Diff line
@@ -74,18 +74,18 @@ static irqreturn_t timer_interrupt(int irq, void *dummy) 
void read_persistent_clock(struct timespec *ts)

{

	struct rtc_time time;



	ts->tv_sec = 0;

	ts->tv_nsec = 0;



	if (mach_hwclk) {

	if (!mach_hwclk)

		return;



	mach_hwclk(0, &time);



		if ((time.tm_year += 1900) < 1970)

			time.tm_year += 100;

		ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,

	ts->tv_sec = mktime(time.tm_year + 1900, time.tm_mon + 1, time.tm_mday,

			    time.tm_hour, time.tm_min, time.tm_sec);

}

}



#if defined(CONFIG_ARCH_USES_GETTIMEOFFSET) && IS_ENABLED(CONFIG_RTC_DRV_GENERIC)

static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)

arch/m68k/mvme147/config.c

+3 −1
Original line number Diff line number Diff line
@@ -153,12 +153,14 @@ int mvme147_hwclk(int op, struct rtc_time *t) 
	if (!op) {

		m147_rtc->ctrl = RTC_READ;

		t->tm_year = bcd2int (m147_rtc->bcd_year);

		t->tm_mon  = bcd2int (m147_rtc->bcd_mth);

		t->tm_mon  = bcd2int(m147_rtc->bcd_mth) - 1;

		t->tm_mday = bcd2int (m147_rtc->bcd_dom);

		t->tm_hour = bcd2int (m147_rtc->bcd_hr);

		t->tm_min  = bcd2int (m147_rtc->bcd_min);

		t->tm_sec  = bcd2int (m147_rtc->bcd_sec);

		m147_rtc->ctrl = 0;

		if (t->tm_year < 70)

			t->tm_year += 100;

	}

	return 0;

}

arch/m68k/mvme16x/config.c

+3 −1
Original line number Diff line number Diff line
@@ -400,12 +400,14 @@ int mvme16x_hwclk(int op, struct rtc_time *t) 
	if (!op) {

		rtc->ctrl = RTC_READ;

		t->tm_year = bcd2int (rtc->bcd_year);

		t->tm_mon  = bcd2int (rtc->bcd_mth);

		t->tm_mon  = bcd2int(rtc->bcd_mth) - 1;

		t->tm_mday = bcd2int (rtc->bcd_dom);

		t->tm_hour = bcd2int (rtc->bcd_hr);

		t->tm_min  = bcd2int (rtc->bcd_min);

		t->tm_sec  = bcd2int (rtc->bcd_sec);

		rtc->ctrl = 0;

		if (t->tm_year < 70)

			t->tm_year += 100;

	}

	return 0;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE